Electric machine



@Pu-:HOHER ELECTRIC MACHINE APPLlCATlON FILED APR-.14| 1917.

Patented 00's. 11, 1921.

Fig.1

UNITI-:D` STATES OTTO PLETSCHER, OF ALBISIEDEN, SWITZRLAND.

PATENT OFFICE.

ELECTRIC MACHINE.

Specication of Letters Patent. I

Patented Oct. 11, 1921.

. Application led April 14, 1917. Serial No. 162,147. i

(for which I Switzerland, and I do be a full,

for instance, adapted to be conveniently carried and operated byV hand and yet abl rent for the production of a light in electric pocket lamps. The machines according to this invention are also adapted to generate .cars orv the like, or .they be used in an ignition apparatus for internal combustion engines, or in connection with electric telephony or telegraphy.

The great diiliculty to be overcomein the production of such electric machines, parare of a very small size, lies in the provision of a sufficiently strong magnetic field by means of permanentmagnets@ i This diiculty is now overcome in my proved construction which comprises, briefly stated, a held-magnet having the shape of a closed, hollow cylinder inclosing the armature and composed of pairs of semi-circular permanent magnets arranged side by side in the longitudinal direction of the cylinder, the opposite magnetic poles of the same sign of each pair separated by a g being connected by suitable means, for instance a pole-piece or the like. A revolving movement may be imparted thereby either to the armature or the liel magnets. a type ofmagneto-electric machine is generally known. But in making such machines e to generate a cur# f poses and the like.

have overcome this diliculty by making the gap between the half-ring magnets not greater than the thickness of the magnets, and placing a pole piece in direct contact with and overlapping the adjacent ends of the magnet, said pole piece being of lesser thickness than the width of the gap at its narrowest part, preferably adjacent the pole piece. The invention consists also in certain features of and combination of parts, all of which will be fully set forth hereinafter and particularly pointed out in he invention will now be more particularly described with reference to the accompanying drawing, which lillustrates a constructional exampleof the invention.

his drawing: ignre 1 is a longitudinal cross-section of this embodiment.

Fig. 2 is a cross-section on the line II-II of Fig. 1 and d Fig. 3 is a side view of this embodiment. In carrying the `invention into effect as shown on the drawing I provide a .two-pole armature 1y having a rib 2 connecting its two pole-shoes. 3 denotes a winding wound around the rib 2. The armature 1 is fixed between two plates 4, th is fixed to a shaft 5 ets and therefore also of the armature 1. shaft 5 and 6, respectivel. bearing 8 surrounded by a Each carries a'ballbox-like ring 9. side hasV a p ripheral groove 17 adapted to receive an suitable driving means. A cylinder of brass 10 arranged between the two rings 9 and preventing a magnetic leakage or dispersion is fixed to said rings 9. Cylinder 10 carries six pairs of semi-circular permanent ymagnets 11, 12, which are not made of steel but of ordinary steel. is provided between adjoining magnets.

As shown in Fig. 2, also the poles of the two magnets 11, 12 of eac pair do not touch each other as I provide a gap 13 between the two opposite magnetic poles of permanent ield magnets,

the same sign. Two pole-shoes 14 are provided on the inner' side or the semi-circular magnets 11, 12 of each pair inclosing to` gether a circular space. Said slices 14 connect the poles of the same sign of each pairI of magnets and they are fixed to the cylinder 10. rlhe stationary armature 1 is arranged between these pole-shoes 14 between which the lines of force ow along a straight line. No magnetic dispersion takes place between the lshoes 14, so that a lield ot great density is formed. The ends of the wire 15 wound around the armature l pass through the hollow shaft 6. Any suitable device, for instance an electric lamp or the like, may be connected in a well known manner to the ends of the wire 15. The brass cylinder 10 is surrounded by a covering 16 which may be made, for instance, ot leather.

As already stated, the rings 9 together with cylinder 10 and the permanent magnets 11, 12 and the pole-shoes 14 may be4 moved relatively to the stationary armature 1 by means of any suitable driving member cooperating with reress 17. ln the embodiment shown a current is generated in the armature 1 as soon as the permanent magnets 11, 12 are rotated at a speed of about 1400 revolutions.

What l claim is:

1. In a magneto-electric machine, arcuate permanent field magnets, spaced apart to form a gap that increases in width toward the outer periphery oi said magnets and a pole shoe connecting poles of like sign on opposite sides of said gap.

2. 1n a magneto-electric machine arcuate spaced apart to orm a gap that increases in width toward the outer periphery of said magnets, pole slice connecting poles oi" like sign on opposite sides of said gap ness less than the minimum the poles.

distance between 3. A magneto-electric machine having spaced, arcuate iield magnets, and pole pieces connecting the ends oi said magnets and spanning` the space between said magn nets; in combination with a non-magnetic casing `and means passing through the gap anda v and of thickf connecting said casing holding the latter .in magnets.

4. In a magneto-electric machine, arcuate permanent field magnets spaced apart to form a gap that increases in width `toward the outer periphery of said magnets and a pole shoe connecting poles of like sign on opposite sides of said gap, and said gap having its least dimension at the shoe.

5. Anelectric machine comprising a field magnet having the shape of a closed, hol low cylinder and composed of pairs of semi circular permanent magnets arranged side by side in the longitudinal direction of the cylinder, the opposite magnetic poles of the same sign of each pair of magnets being separated yby a gap increasing in width toward the periphery of said magnets, pole shoes fixed within the cylinder and connecting the opposedmagnetic poles of the same sign of the magnets of a pair, two box-like rings, each fixed to an end of said cylinder, one or said rings arranged to cooperate with means for rotating said cylinder, an armature inclosedby said cylinder and having two pole-shoes common to all` the magnets and a rib connecting the armature poleshoes, the width of which. shoes corresponds to that of the pole shoes ofthe magnets, a winding on this rib, a hollow `and a solid shaft, one of lsaid shafts being arranged on one side and the other on 4the opposite side ot' said cylinder, plates rigidly connecting these shafts to thearmature, and stationary bearings for said shafts preventing a rotation of the latter` the ends of said winding passing through the hollow shaft.

G. In a magneto-electric machine, elements arranged side by side, composed, of substantially semi-circular magnets having a gap between them widening toward their outer peripheries, and pole shoes common to all the magnets connecting the opposed poles of like sign or' said magnets, said pole 'shoes of less thickness than the minimum width of said gaps.

In testimony that l claim the as my invention,

and pole pieces and Contact with said field each element foregoing I have signed my name.

TTO PLETS CHER. 

